A fuel injector may be used to inject fuel into an internal combustion engine by atomizing the fuel under high pressure and injecting the atomized fuel into a combustion chamber of the engine through a nozzle of the fuel injector. Some fuel injectors include a solenoid used to control the fuel injection, which generates heat during operation. The solenoid may be located in the middle of the body of the fuel injector, and cooling the solenoid may be difficult, particularly when the engine is operating at high speeds and high injection pressures. Heat may also be generated in the fuel injector due to spilled hot fuel, internal leaking of the fuel injector, and/or the like.
Cooling the solenoid and/or other components inside the fuel injector may be even more difficult if the fuel injector is seated in a unit cylinder head (where each cylinder of the engine has a single corresponding cylinder head) because low pressure cooling fuel may flow in parallel through each cylinder head along a fuel rail (e.g., a fuel supply and drain rail, a fuel supply and return rail, and/or the like). In this configuration, each successive fuel injector along the fuel rail may experience less fuel flow and/or hotter cooling fuel, which reduces cooling efficiency. Furthermore, if the fuel supply inlet and the fuel return outlet are positioned on the same side of a fuel injector, then the cooling fuel may flow from the fuel supply to the fuel return without passing through the fuel injector case and/or without cooling the solenoid.
One attempt to improve cooling of fuel injector solenoids is disclosed in U.S. Pat. No. 8,434,457 that issued to Coldren et al. on May 7, 2013 (“the '457 patent”). In particular, the '457 patent discloses a fuel injection system that provides a greater balance in the operating temperatures of the fuel injectors by providing a lower cooling rate for fuel injectors disposed upstream on the fuel rail and a higher cooling rate for fuel injectors disposed downstream on the fuel rail. Such cooling rates may be provided by manipulating the size of the slots or openings in the nozzle cases of the fuel injectors, and/or manipulating the flow rate of fuel supplied to an injectors as coolant flows between the nozzle case and solenoid assembly.
While the fuel injection system of the '457 patent may provide a greater balance in the operating temperatures of the fuel injectors along a fuel rail, there may still be cooling inefficiencies for each individual fuel injector. The fuel injector of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.